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Photo Credit: H Vannoy Davis
Kern Primrose Sphinx Moth
Basic Species Information
Threatened. The species is likely to become endangered in the foreseeable future throughout all or a significant portion of its range, but they are not in danger of extinction right now.
The Kern primrose sphinx moth is one of three species within the genus Euproserpinus, which are members of the Sphingidae family, commonly called hawk moths or sphinx moths.
This is a moderate sized, diurnal (day-flying) moth. It has a streamlined yet stout body and elongate forewings that are oblique at the outer margins.
Adults are distinctly marked by a broad and contrasting white band on the abdomen, convex costal margins of the hindwing and forewing, and white scaling on the dorsal surface of the antenna.
The colorful larvae are without hair or spines. The dorsal part of the eighth abdominal segment contains a horn or spur.
Adults nectar on a variety of flowering species that occur in the region, including, filaree, goldfields (Lasthenia chrysostoma), baby blue-eyes (Nemophila menziesii) and miniature lupine (Lupinus bicolor).
Flight periods for the adults range from late February to early April. However, pupae are known to diapause (delay metamorphosis to adult form) underground for multiple years during drought periods.
The 0.1 cm (0.04-inch), light green eggs are laid on evening primrose (Camissonia contorta epilobiodes) and on filaree (Erodium cicutarium). Larvae emerge from the eggs a few days after oviposition and begin to feed.
At the time of listing, the nonnative, invasive, low-growing weedy plant, filaree (Erodium sp.), was thought to negatively impact the Kern primrose sphinx moth at the Walker Basin because it was noted that female moth oviposit on nonhost plants and other objects.
Subsequent observations revealed that the first instar (growth period between molts in larval insects) larvae is actually capable of making forays from nonhost plants across open ground to find host plants if the individual host plants are of adequate density. This means Kern primrose sphinx moth oviposition on filaree does not necessarily lead to death of the hatching larvae.
At the time of listing, the Kern primrose sphinx moth was known from only the northwest portion of the Walker Basin, primarily on 4,000 square meters (43,053 square feet) of a sandy wash.
In 2002 and 2003, three populations were discovered for the first time at the Carrizo Plain in San Luis Obispo County, about 120 km (75 miles) west of the Walker Basin population.
See our 5-year review for more information about the species’ distribution.
Since listing, the primary threats to the Kern primrose sphinx moth are agricultural land use practices that degrade the habitat, particularly cattle grazing, disking, using pesticides and herbicides and development.
Sheep grazing can be both beneficial and harmful to the Kern primrose sphinx moth. Although grazing is used to control invasive weeds, grazing animals can trample the moth eggs, larvae, and pupae, as well as the host plant. Sheep grazing and trailing are considered a threat at this time only to those few Carrizo Plains Kern primrose sphinx moth populations and has not been observed at the Walker Basin or the Cuyama Valley.
Many agricultural pesticides are specifically designed to target insect larvae (caterpillars) as well as adult moths. Some herbicides have also been found to negatively impact a variety of insects. Agricultural practices in the Central Valley include spreading thousands of tons of pesticides and herbicides annually, which can be spread beyond the target area by prevailing winds and have been implicated in affecting animals many miles downwind of applications. All Kern primrose sphinx moth populations are potentially at risk from this effect.
At the time of listing, collectors had removed a significant number of moths, the majority of which were the slower flying and, thus, easier-caught females. Illegal collection for commercial purposes remains a threat.
Last updated: December 1, 2017